Multiple-turret target-indicator.



E. A. SPERRY.

MULTIPLE TURRET TARGET INDICATOR.

APPLICATiON FILED AUG.3I. x914.

Patented Mar. 4,1919.

3 SHEETS-SHEET l.

WITNESSES.- 3 INVENTOR,

- 6. .Wm. QMEAAGPEQRX aiywm W#% ATTORNE E! A. SPERRY.

MULTIPLE TURRET TARGET INDICATOR-1 APPLICATION FILED AUG. 31.1914.

Pateilted Mar. 4,1919.

HEET 2- s' NGRRIS PEYERS ca, PNDYD'LIYNQ. WASHINGTON. n. c.

E. A. SPERRY.

MULTIPLE TURHET TARGET INDICATOR.

APPLICATION FILED AUG-3| I914.

Patented Mar. 4,1919.

3 SHEETS-SHEET 3- LEW??? IN V EN TOR.

W .m MW Y WITNESSES pnrru STATES PATENT OFFICE.

ELMER A. SPERRY, OF BROOKLYN, NEW YORK, AS-SIGNOR TO THE SPERRYGYROSCOPE COMPANY, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

MULTIPLE-TURRET TARGET-INDICATOR.

Specification of Letters Patent.

Patented Mar. 4, 1919.

Application filed August 31, 1914. Serial No. 859,329.

To all whom it may concern:

Be it known that I, ELMER A. SPERRY, citizen of the United States,residing at Brooklyn, N. Y., have invented a new and useful Improvementin Multiple-Turret Target-Indicators, of which the following is aspecification.

This invention relates to indicating means adapted to be placed within aturret of a war vessel and to show the direction in which the turretshould be pointed, the actual position of the turret at each instant,and preferably in addition the position of other turrets on the ship. Myinvention is capable, also, of many other uses, as will be apparent tothose skilled in the art.

Heretofore great difiiculty has been experienced in the proper aimingand firing of the big guns in the turrets, due principally to thefollowing causes :difliculty in locating the proper target from the turrot and interference with the guns in an adjacent turret. According tothe present system, the spotter telephones down to the turret operatorthe approximate position of the target at which he is to aim, such astarget on the starboard bow, etc. The turret is then swung slowly arounduntil the target is sighted through the telescope. But this has proved aslow and unreliable procedure as the operator may have to search for thetarget quite a while before he picks it up and since, as frequentlyhappens, the Wrong target is picked up, especially where there are twotargets close to each other. Again, when adjacent turrets are firing atdifierent targets, there is constant danger of the guns in one turretshooting the muzzles ofi the guns in the adjacent turret.

The object of my invention is to provide an indicator which will embodyin one instrument a means whereby a turret. may be trained quickly onthe right target and whereby all danger of interference with an adjacentturret is obviated.

Another object of the invention is to improve the construction ofindicators of this general nature whereby a repeating indicator may beset from the master or controlling indicator when it has fallen out ofstep therewith, and whereby the reliability of operation of saidrepeating system is improved.

In the drawings forming a part of this specification, one embodiment ofmy invention is shown.

Figure 1 is a top plan View of an indicator for use in a turret.

Fig. 2 is a bottom plan view of the same with the back plate removed.

Fig. 3 is a section on line 3-3 of Fig. 2.

Fig. 4.- is a diagrammatic illustration and wiring diagram of mycomplete system as installed in two turrets.

Fig. 5 is a detailed view of a brake or stop mechanism for the repeatermotor.

Fig. 6 is a detail of a turret transmitter.

Fig. 7 is a detail of the magnetic lock used in the synchronizingsystem.

Fig. 8 is a view of a modification corresponding to Fig. 2.

Fig. 9 is a wiring diagram therefor.

Fig. 10 is a side elevation of one of the double throw switches shown inFig. 8.

Fig. 11 shows a modified form of a brake or stop mechanism for therepeater motors.

Indicator 1 is equipped with a plurality of repeater motors, preferablyof the stepby-step type, one motor 2 being actuated by a. transmitter 3on its containing turret A. another motor 4: from a transmitter 5 on anytype of target bearing indicator or instrument I, while the remainingmotors are actuated by transmitters in adjacent turrets. While I haveshown only one such turret B, motor 6, and transmitter 7 it is obviousthat my system may be made to include any number of turrets and motors.In each adjacent turret a similar indicator is mounted, comprising motor2, actuated preferably from said transmitter 7, motor 4, similar tomotor 4, and motor 6', actuated preferably from said transmitter 3, thesame transmitter being used to control the motor within its own turret,and other motors in each of the other turrets. Since eaclr'indicator issimilar in construction, a detailed description of indicator 1 will onlybe given.

Suitable position indicators are arranged to be actuated from themotors, comprising a turret position indicator or pointer a for thecontaining turret A, actuated from motor 2, a target position indicatoror pointer 0, actuated from motor 4, and a position indicator 1) foradjacent turret B, actuated from motor 6. Circular graduations 8 and 12,engraved on a fixed plate 10,

cooperate with turret indicator pointer 00 and pointer 79 and turretindicator polnter Z), respectively.

The indicators are so arranged that the pointers a and b which are shownas a, miniature representation of the turrets Wlll actually cross eachothers path within the entire danger zone. Each indicator pointer may bein the form of an irregularly shaped disk of the general outline of theturret and guns with markings 8O thereon representing the guns andturret. Hence the centers of rotation of the indicator pointers a and bare at least as close together in proportion, or if desired somewhatcloser, than the distance between the turrets A and B, the idea being toindicate graphically and clearly the positions of danger by theintersections of the dials. In order to place the dials so that theirpaths of movement intersect, graduations 9, on a cover plate 10, arealso provided, extending from the zero position around only 90 in eachdirection. on which scale the pointer 11 reads, while the re mainder ofthe scale, or a portion thereof 12, is laid out adjacent the firstportion on plate 10 and is read in connection with pointer 13. It shouldbe noted that the graduations on the last named portion of the scalebetween 150 and 210 are omitted. This is purposely done to indicate thezone in which the guns of turret 5 would strike a fixed portion of theship. The target bearing indicator or pointer p is preferablyconcentrically mounted with respect to the indicator a of the containingturret, whereby the turret officer is provided with a ready and simplemeans for indicating when the turret is trained on the target. Othermeans for accomplishing a similar result will be obvious to thoseskilled in the art.

The whole of the indicating mechanism is shown as inclosed in a casing33, provided with a glass cover 34 and a back plate 35. The motors andthe transmission mechanism are supported by a pair of plates 36, 37,which are secured in spaced relation to each other by posts 38, plate 37being removably secured to the casing 33 by set screws 39.

Taking up now the specific construction of the indicator, including thetransmission system between the motors and the dials, motor 2 isprovided with a pinion (not shown) which drives a gear 14 secured toshaft 15. Also secured to shaft 15 is a pinion 16 which drives the largegear 17 secured to sleeve 18, carrying directly the turret pointer a.Similarly, motor 4 drives the large gear 19 through reduction gears 20and 21. Said gear 19 is secured to central shaft 22 by means of hub 23.The shaft extends freely through sleeve 18 and carries adjacent itsupper end pointer p. In like manner motor 6 controls indicator Z)through reduction gears 24 and 25 and large gear 26 on the hub of whichis secured the dial.

In order to set the pointers in the proper position with respect to theturrets, when the indicator is being set up or in order to correct it incase it should fall out of step, local synchronizers in the form ofsetting handles 27 are provided for the indicators. Each handle ismounted on a shaft 28 carrying adjacent its other end a crown gear 29. Aspring 30 normally holds gear 29 out of mesh with a gear 31, mounted onthe same shaft as the reduction gearing of each group, but by pushing inon the proper handle 27, a crown gear 29 can be brought into mesh withone of said gears 31, and the dial rotated by hand. Screw caps 32 may beprovided to cover said handles 27, preventing accidental operationthereof.

As a further means for setting the pointer 29 properly, an electric stopis provided which operates to lock the polnter when it has reached apredetermined position, thereby providing a long distance synchronizerwhich sets directly from the target bearing indicator I. This meanscomprises a button 40 mounted on gear 19, which wipes over a pair offingers 41 fixed on the frame. When the button is in the position shownin Fig. 2, a circuit is completed through the fingers. In the samecircuit 0 with the fingers 41 is a hand operated switch 42 on orassociated with the target bearing indicator, so that the circuit willonly be closed when both switches are closed. This circuit 0 is arrangedto operate a solenoid 43, the armature 44 of which carries a pin 45adapted to engage in a notch 46 in a collar 47 on the shaft of the motor4, when the solenoid is energized. A spring 48 holds the pin 45 normallyout of said notch. In order, then to lock the indicator, not only mustthe gear 19 carrying button 40 be in a predetermined position and theswitch 42 on the indicator be closed, but also the motor shaft must haveassumed such a position that the notch 46 is under the pin 45. Thisenables the pointer 79 to be adjusted with a great degree of accuracy,since the motor is connected so that one of its steps equals only a verysmall arc of movement on the pointer, while the pin and notch insure thelocking of the motor at exactly the correct position:

A further aid to the same end is to equip the gear 20 also with a button49 (Fig. 2) which wipes over stationary fingers 50 in the same circuitwith the other two switches and solenoids 43. In such a case all threebuttons must be in the circuit closing position snnultaneously, and atthe same time that notch 46 is under locking pin 45 before pointer 79will be locked. The buttons 40 and 49 and the notch 46 are so placed asto lock the pointer p in a predetermined known po- S1t1011, such as thezero position. After the pointer is locked the operator of indicator Icontinues to rotate it until it also reads on the same position as thepointer 77, or in other words, the operator brings the indicator I alsoto the zero position. As soon as this position is attained said circuit0 is broken by the operator at button 42 leaving circuit (Z throughmotor 4 and transmitter 5 closed so that the pointer will follow themovements of the indicator 1. It will be understood that the othermotors may be equipped with such a. look if desired.

In addition to the button 42 another switch 120 may be put in thecircuit 0, the purpose of which is to break said circuit when thesetting handle 27 is used. From what has already been said, it will beapparent that the handle 27 may be used to synchronize a dial to anyposition of the master instrument, so that it is desirable to have apositive means for preventing the lock 45 from acting when synchronizingin this manner. Switch 120 is readily connected to the setting device bymeans of a bell crank lever 121 pivoted on a fixed rod 122 and securedadjacent one end to a rod 123, which slides freely in a bearing 124 andbears against the outer face of crown gear 29. The spring 30 which holdsthe gear 29 disengaged presses the lower end of bell crank lever intoengagen'ient with the switch 120, holding it closed, but when the crowngear is moved forward into engagement with gear 31 the spring 124 isallowed to open the switch. By this means all interference between thetwo setting systems is avoided. I prefer to equip each of the repeatermo tors with a novel form of stop or lock which is adapted to preventthe motors from rotating when they are not in use. I find such a stopespecially serviceable on motors connected so that the rotation of onewill have a tendency to rotate another, such as where they driveconcentric-ally arranged sleeves, like shaft 22 and sleeve 18, whichhave a sliding contact with each other. The stop is also useful insetting adial by handle 27, since it prevents the dial from coastingpast the desired position, upon release of the handle.

Specifically, the stop consists of a spring pressed friction block 51,which bears on a collar 52 on the shaft of the motor and secured to thepivoted armature 53 of elec tro-magnet 54. A spring 55 holds the brakeset normally, but by placing the magnet 54 in the motor circuit, meansare provided to hold the stop or brake in an inoperative position duringthe time that the motor is energized. Magnet 54 is shown as supportedfrom a plate 56 secured to the motor frame. The brake is designed sothat while it will prevent accidental rotation of the motors, it willnot interfere with turning them from handles 27, but rather assists theaccuracy of hand setting as pointed out above.

As this invention in its broad aspect is independent of the specifictype of step-bystep motors and transmitters used, and as this type ofmotor is well known, a detailed description of their action andconstruction will be omitted. In the wiring diagram the transmitters areshown as three pairs of coir tact points adapted to be brought incontact in succession by the movement of the controlling means. Aconvenient means of accomplishing this result is shown in Fig. 6, whichillustrates one of the turret transmitters 3. This transmitter isdesigned to be secured so that the gear 57 will mesh with an internalgear on the turret A. Gear 5 rotates the commutator 58 throughmultiplying gears 59- and 60. The commutator is made in three sectionsand each section is provided with two diametrically opposite 90conducting strips 61 grounded to the frame and spaced by insulatingblocks. The strips on each section are arranged 30 ahead, so that sixdifferent steps are provided for the six pole motors, one step directlyunder each pole when onebrush 62 only is on a conducting strip, and onestep between each pair of poles when two brushes are on conductingstrips.

The target bearing indicator I may assume any form. It is shown as adial with a transmitter 5 attached and operated manually by handle 65.It may be made a part of target bearing telescope and located in thefighting top or it may be located at the sub-central station on thebattle ship, Where the operator may not only receive the true bearingsof the target but may, if desired,

apply the proper corrections for drift, etc.,

in setting the indicator, so that the guns will always be pointed inexactly the same direction as indicated by the pointer.

It should be noted that this system has the further advantage that theturret may be set in the proper position in azimuth without sightingfrom the turret. This makes an important advance in the art, since veryoften a target is visible from the fighting top when it is obscured bysmoke or fog from the turret.

In Figs. 8 to 11 a modification is shown which related more particularlyto the local setting or synchronizing means. In place of a settinghandle 27 for each dial, I use a single setting handle 27 and set thedials electrically from it, using switches 100, 101 or 102 to throw theselected motor into circuit with a transmitter 103 operated by thehandle. The shaft of handle 27 is preferably provided with. a notchedcollar 104 against which a roller 105 is held by the spring 106 whichsupports it. The notch and roller are positioned so that when they arein engagement, the motor armature being actuated from the transmitterwill be under a certain pole, thus increasing the &

accuracy of the setting or synchronizing operation, through anexpediency similar to that described in connection with contact fingers11 and 42. The transmitter 108 is shown as of the same type asheretofore described. The switches 100, 101 and 102 are shown as of thedouble throw type. Each switch comprises a plurality of blades 107onpins 108 and connected by a rod 108. A spring 109 connects a block 110secured to said rod to the casing, pulling blades 107 into engagementwith the fingers 111, which are connected to one of the mastertransmitters as shown in Fig. 9. A push button 112 is connected to eachswitch through block 110. By pushing in on the button, the blades arethrown between fingers 113, connecting a motor with the synchronizingtransmitter 108. Rotation of this transmitter through handle 27 willthen set the corresponding dial. A switch 120 may also be provided whichcorresponds in function to switch 120 in the other form of theinvention. Like switch 120 it is placed in the circuit 0 of the lockmagnet 43. It is preferably made a part of the switch 100, so that whenthe button 112 connected to said switch is pushed in said circuit isbroken. It should also be noted in connection with Fig. 9 that it showsthe electrical connections where one source of power 114 is used for allthe circuits. It is obvious that a single source of power could also beused in the circuits shown in Fig. 4 if so desired.

Fig. 11 shows an alternative form of stop or brake from that shown inFig. 5. In this form of stop a more positive form of engagement issecured by providing the armature 53 with a tooth 51 to engageserrations on the collar 52. Thi form of brake is especially adapted foruse in connection with the modification shown in Figs. 8 to 10 since thebrake will be disengaged by the electric circuit through the settingtransmitter and motor and hence the positive engagement between themwill not interfere with. the local synchronizing of the indicator. Inthis form it should be noted that both brake 51 and lock 48 both ofwhich may generally be termed locks are rendered inoperative onoperation of the local synchronizing means.

The general operation of my system is as follows :When the ship is goinginto battle or target practice, each turret indicator is set by handles27 or handle 27 at the position in which the turrets are then placed.The pointer p may be set in a similar manner if the position of thetarget bearing instrument is known or it may be set directly from saidinstrument by means of the lock 43, as explained above. When theindicator is synchronized, the current is then turned on through themotor coils, so that they will follow every movement of their respectivetransmitters. As soon as the operator of the indicator I, locates thebearings of the target, if it is used on the target bearing telescope,or is informed of the bearings and range of the target, if it isoperated in the sub-central station, he turns it so that it willindicate said bearings, or still better in the latter alternative sothat it will indicate the direction in which the gun should be aimed, byapplying the above noted corrections.

s he turns indicator I, the pointer p in each turret Will keep in step.The turret operator then revolves his turret so that indicator pointer ais directly under pointer 72, unless he notes that such a position willinterfere with the adjacent turrets, by observing the position ofpointer 72 with respect to indicators 6. In such a case propernotification could be given either to the operator of the adjacentturrets or the sub-cen tral station. After locating the target andapplying the proper elevation to the guns, the operator may either firethe guns immediately or he may take sights on the target himself andapply whatever correction he finds necessary.

In accordance with the provisions of the patent statutes, I have hereindescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.Also, while it is designed to use the various features and elements inthe combination and relations described, some of these may be alteredand others omitted without interfering with the more general resultsoutlined, and the invention extends to such use.

Having now described my invention, what I claim and desire to secure byLetters Patent is:

1. A turret indicator system comprising a plurality of turrets, anelectrical transmitter in each turret actuated by the rotation of theturret, a plurality of position indicators in each turret, eachtransmitter being connected to a position indicator in each turret.

2. A target turret indicator system comprising a transmitter connectedto a turret so as to be actuated thereby, a position indicator in theturret connected therewith, a transmitter on a target bearinginstrument, and a target bearing indicator connected therewith andmounted adjacent said position indicator.

3. An indicator for turrets comprising a position indicator adapted toshow at each instant the position of its turret and a pointer mountedadjacent thereto and means whereby said pointer is caused to repeat themovements of a distant target bearing instrument.

4:, A target bearing indicator system com prising a position indicatorin the turret connected so as to rotate with the turret, and a targetbearing indicator connected therewith and mounted adjacent said positionindicator.

5. A multiple turret indicator system comprising a plurality of positionindicators in each turret, each indicator being arranged to rotate instep with one of the turrets, and a target bearing indicator in eachturret mounted adjacent the position indicator for the inclosing turret,and arranged to rotate in step with a target bearing instrument.

6. A target bearing system for turrets, comprising a master instrumentadapted to be set to show the actual position in which the turretsshould be placed, a position indicator adapted at each instant toindicate the position of the containing turret, and an indicator adaptedto be controlled at a distance from said instrument and to be placedadjacent said position indicator, whereby the guns may be aimed withoutsighting from the turret.

7. An indicator for turrets comprising a position indicator adapted toshow at each instant the position of its turret, and a pointer mountedconcentrically therewith and adapted to repeat at a distance themovements of a target bearing instrument.

8. In an indicating system for turrets, a position indicator adapted toshow the position of an adjacent turret, and a target indicator mountedadjacent said position indicator and adapted to show the targetbearings, whereby the opberatormo f the turret anticipate; aninterference between the turrets.

9. A target bearing system for turrets, comprising a master instrumentadapted to be set to show the actual position in which the turretsshould be placed, a position indicator adapted to show the position ofthe containing turret, a second indicator adapted at each instant toindicate the position of an adjoining turret, and an indicator adaptedto be controlled at a distance from said instrument and to be placedadjacent said position indicator, whereby the guns may be aimed withoutsighting from the turret.

10. In a repeating system, the combination with an indicator adapted torepeat the movements of a distant master controller, of an electricallycontrolled lock mounted on said indicator, a plurality of controllingswitches for said lock, including a switch controlled from said mastercontroller, and a switch controlled from said indicator, whereby saidlock is actuated only when both the controller and indicator switchesare closed.

11. In a repeater system, the combination with a repeater motor, anindicating means, and a train of reduction gearing between said motorand indicating means, of an elec- .tric lock associated with said systemadapted to lock the indicator, and controlling switches for said lockmounted upon a plurality of gears in said gear train, whereby the lockis actuated only when the indicator has reached a predeterminedposition.

12. In a repeater system the combination with a plurality ofconcentrically arranged. indicators, a repeater motor for eachindicator, and a brake on each motor adapted to prevent rotation of theconnected indicator when its motor is not energized.

13. In a repeating system, the combination with a repeater motor, anindicating means, and reduction gearing between said motor andindicating means, of a lock for said means comprising a notched collaron a. rotary part of said system, of relatively high velocity, a fingermovable on a part of the system, and means for causing said finger toengage the notch controlled by the relative position of the indicatingmeans whereby accurate setting is obtained.

14. In a repeater system, the combination with a repeater motor, anindicating means, and reduction gearing between said motor andindicating means, of a lock for said means comprising a notched collaron said motor shaft, a movable finger adapted to engage said notch, anelectromagnetic means for controlling said finger, and an electricswitch in circuit with said means positioned so as to be closed when theindicator reaches a predetermined position.

15. In a repeater system, the combination with a repeater motor, anindicating means, and reduction gearing between said motor andindicating means, of a lock for said means comprising a notched collaron said motor shaft, a movable finger adapted to engage said notch,electromagnetic means for controlling said finger, and a plurality ofelectric switches connected in series in circuit with said means, saidswitches being positioned on different gears so as to rotate atdifferent speeds, whereby the indicator will be locked only when theindicator itself, the transmission gears and the motor are in thecorrect position.

16. In a repeater system the combination, with a master indicator, of arepeater motor. and indicator, reduction gearing between said motor andindicator and a setting handle adapted to be brought into operativeengagement with said gearing whereby said indicator may be set tocorrespond with the master indicator.

17. In a repeater system, thecomb-ination with a master indicatoradapted to be set in predetermined positions, a switch adjacent thereto,and a repeater indicator controlled thereby, of an electricallycontrolled lock for said indicator in circuit with said switch, a secondswitch for'said lock mounted to rotate with said indicator, whereby saidrepeater indicator may be properly set by closing said first switch androtating said master indicator. Y

18. In a repeater system, the combination with anindicator adapted toreproduce the movements of a master controller, of an electricallycontrolled lock adapted to lock the indicator in a predeterminedposition, whereby it may be set from the master controller a localsetting means adapted to set the indicator directly, and a switch incircuit with said lock connected with said means so that said lock willbe rendered inoperative when said means are operated.

19. In a repeater system the combination with a repeater and acontroller, of a long distance regulating means for setting the repeaterfrom the controller, a local regulat ing means mounted on said repeater,and means for rendering one of said means inoperative when the other isactuated.

20. In a repeater system the combination with a repeater and acontroller, of a long distance regulating means for setting the repeaterfrom the controller, and a local regulator mounted on said repeater.

21. In a repeater system the combination with a controlling instrument,of a repeat ing indicator adapted to be controlled from said instrumentcomprising a motor, an indicating dial, reduction gearing between saidmotor and dial and means whereby said dial may be synchronized from saidinstrument.

22. In a repeater system the combination with a controlling instrument,of a repeating indicator adapted to be controlled from said instrumentcomprising a motor and indicating dial, reduction gearing between saidmotor and dial and means whereby said dial may be synchronized from saidinstrument comprising a lock on said indicator controlled from saidinstrument.

23. In a repeating indicator, an indicating means, a stop or lookoperatively connected with said means, a local setting device for saidmeans, and means for rendering said stop or look inoperative when saiddevice is operated.

24. In an indicator, the combination with a plurality of concentricallyarranged indicators, a repeater motor for each indicator, an electricoperating means for each motor and a positive means for locking anindicator when disconnected from its operating means whereby it will notbe thrown out of position by the operation of the other indicator.

25. In a repeater system, the combination with a sending instrument, ofa repeating indicator, a motor connected to said indicator adapted tocause it to repeat at a distance the movements of said instrument, and alock associated with said indicator, adapted to lock it when it hasreached a predetermined position.

26. In a repeating system, the combination with a sending instrument anda transmitter connected thereto, of a repeating indicator comprising arepeater motor adapted to be actuated from said transmitter, anindicator controlled by said motor, a normally in operative lock forsaid motor and indicator, adapted when excited to lock the indicator ina predetermined position and means located adjacent said sendinginstrument for operating said lock.

27. In a gun fire control system, a transmitter adapted to transmit thebearing of a target, a turret position transmitter, a receivinginstrument operatively connected to both transmitters and means, in saidreceiving instrument, for indicating when the turret is trained on thetarget.

28. In a gun fire control system, a target bearing transmitter, a turretposition transmitter, a receiving instrument operatively connected tosaid transmitters and means including a pointer in said receivinginstrument for indicating when a turret is trained on a target.

29. A tell-tale indicator comprising a plurality of concentricallyarranged rotatable indicators, concentric hubs and driving gears forsaid indicators, a step-bystep motor for each of said gears, meanswhereby a motor may be rendered inoperative and a magnetic stop for amotor adapted to prevent the connected indicator from being rotated byrotation of the other indicators, when said motor is inoperative.

In testimony whereof I, ELMER A. SPERRY. have signed my name to thisspecification in the presence of two subscribing witnesses. this 26thday of August 1914.

ELLIER A. SPERRY.

Witnesses:

L. J. DIBBLE, EVERETT W. MARKES.

Copies of thin patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

